The latest U.S. public opinion poll shows a majority of Americans now believe President Bush exaggerated Iraqi threats to justify the U.S.-led invasion that toppled Saddam Hussein.

A Washington Post/ABC News survey shows 54 percent of those questioned believe President Bush either lied about, or deliberately exaggerated the threat from Iraqi weapons of mass destruction.

The immediacy of that threat was the president's biggest justification for invading Iraq. But U.S. inspectors have so far not found any of those weapons, prompting the president to appoint a commission to figure out what went wrong with U.S. intelligence.

The survey results released Friday show public approval for the president's handling of the situation in Iraq has fallen to 47 percent, down eight percentage points in the past three weeks. Less than half of Americans now believe the war was worth fighting.

The president has also seen a drop in his personal ratings, with 52 percent of Americans responding that Mr. Bush is "honest and trustworthy." That is his lowest ranking since 1999. By comparison, 71 percent of Americans felt Mr. Bush was honest in the middle of 2002.

The poll of 1,000 randomly selected adults shows Massachusetts Senator John Kerry would beat President Bush in a head-to-head vote 52 percent to 43 percent. Senator Kerry is the front-runner to win the Democratic nomination to challenge the president in this year's election.

Republican officials had expected the president's poll numbers to drop during the Democratic primaries, as voters hear more attacks against Mr. Bush.

White House Spokesman Scott McClellan dismissed suggestions that the declining poll numbers might be related to the failure to find Iraqi weapons or questions about the president's military service during the Vietnam War.

He says Mr. Bush does not pay great attention to polls, and is concentrating instead on his job as president. "We are focused on the priorities here," he said. "But the numbers that you are seeing, I think, are not out of line with the historical pattern. You have to keep in mind that there have been a lot of dramatic twists and turns in the Democratic primaries, and that is where all the attention has been focused. That has been the only game in town. There is going to be plenty of time to talk about the election down the road."

The Bush-Cheney campaign has resources of nearly $100 million, and plans to start running its first television commercials sometime next month.

The campaign has run its first direct attack against Senator Kerry with an Internet-based video calling the Democratic front-runner "unprincipled" because of the money he has accepted from special interests.